Where else do developers hang out?

I like StackExchange sites. My favorites stackoverflow.com and programmers.stackexchange.com You can chat with people there, discuss the white-board questions etc

Reddit's programmer subs are pretty nice, although they tend to be inactive for smaller languages/tools/topics.

Do people still use IRC? Where is active these days?

IRC channels for projects can be quite lively. The busiest channels I idle in are #ffmpeg-devel and #lua on freenode. Clearly these are dedicated towards these projects but sometimes other chat filters in. #lua certainly gets that.

Others can be much more quiet and be usually for tech support of a project but they can still be a good place to contact people working on a project.

Thanks for all the good suggestions. Appreciate it!

Real-world Meetup.com meetups.

I second this. I am a member of around 7 local developer focused meetups. I go to a meetup at least 1 or twice a month.